U.S. patent application number 12/287941 was filed with the patent office on 2009-06-04 for grill including automatic gap calibration.
Invention is credited to Ronald J. Glavan, Robert K. Newton, Jeffrey L. Sands.
Application Number | 20090139411 12/287941 |
Document ID | / |
Family ID | 40674441 |
Filed Date | 2009-06-04 |
United States Patent
Application |
20090139411 |
Kind Code |
A1 |
Sands; Jeffrey L. ; et
al. |
June 4, 2009 |
Grill including automatic gap calibration
Abstract
A grill includes a lower platen assembly having a lower grilling
surface and a pivotally attached upper platen assembly having an
upper grilling surface. The upper platen assembly includes three
motors encased in a shell. A cable attached to each motor suspends
the upper grilling surface. The grill is automatically calibrated
to ensure that the upper grilling surface is level. Each motor
independently and sequentially raises the upper grilling surface
from the lower grilling surface. When the upper grilling surface
lifts from the lower grilling surface, the current in the motor
changes. The settings of each motor at this instant are stored in a
control to determine the calibration point when the upper grilling
surface is level. The grill also automatically recognizes a food
item placed on the lower grilling surface to determine the cooking
parameters of the grill.
Inventors: |
Sands; Jeffrey L.;
(Freeport, IL) ; Newton; Robert K.; (Beloit,
WI) ; Glavan; Ronald J.; (Rockton, IL) |
Correspondence
Address: |
RYNDAK & SURI LLP
200 W. MADISON STREET, SUITE 2100
CHICAGO
IL
60606
US
|
Family ID: |
40674441 |
Appl. No.: |
12/287941 |
Filed: |
October 15, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/US2006/015157 |
Apr 20, 2006 |
|
|
|
12287941 |
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Current U.S.
Class: |
99/349 ;
73/1.01 |
Current CPC
Class: |
A47J 37/0611
20130101 |
Class at
Publication: |
99/349 ;
73/1.01 |
International
Class: |
A47J 37/06 20060101
A47J037/06; G01D 18/00 20060101 G01D018/00 |
Claims
1. A grill comprising: a lower platen assembly including a lower
grilling surface; an upper platen assembly pivotally attached to
the lower platen assembly, wherein the upper platen assembly
includes an upper grilling surface; and a leveling mechanism to
automatically level the upper grilling surface relative to the
lower grilling surface, wherein the leveling mechanism includes a
plurality of motors that each independently move a portion of the
upper grilling surface to level the upper grilling surface.
2. The grill as recited in claim 1 wherein the leveling mechanism
includes a control that independently controls each of the
plurality of motors.
3. The grill as recited in claim 1 wherein each of the plurality of
motors includes a rotatable shaft having an end, wherein a disc is
attached to the end of the shaft.
4. The grill as recited in claim 3 wherein the leveling mechanism
includes a cable associated with each of the plurality of motors
having a first end and a second end, wherein the first end of each
of the cables is attached to one of the discs and the second end of
each of the cables is attached to the upper grilling surface,
wherein the upper grilling surface is suspended from the
cables.
5. The grill as recited in claim 4 further including a current
sensor that senses current in each of the plurality of motors.
6. The grill as recited in claim 5 further including a control that
independently controls each of the plurality of motors, wherein,
when the leveling mechanism is activated, the plurality of motors
lower the upper grilling surface onto the lower grilling surface,
wherein each of the plurality of motors sequentially raises the
portion of the upper grilling surface and the current in each of
the plurality of motors changes when the upper grilling surface
lifts from the lower grilling surface, wherein the current sensor
detects a change in the current, and wherein calibration settings
of each of the plurality of motors when the current sensor detects
that the change in the current is over a threshold value are stored
in the control to define a calibration point.
7. The grill as recited in claim 5 wherein food is grilled in a gap
between the lower grilling surface and the upper grilling surface,
the current in each of the plurality of motors changes when the
upper grilling surface lifts from the food, the current sensor
detects the change in the current, and a size of the gap is
determined to recognize the food and determine cooking
parameters.
8. The grill as recited in claim 7 wherein the cooking parameters
are one of a cooking time, a cooking temperature and a gap
distance.
9. The grill as recited in claim 4 wherein the rotatable shaft
rotates in a first direction to lengthen each of the cables to
lower the upper grilling surface towards the lower grilling surface
and the rotatable shaft rotates in an opposing second direction to
shorten each of the cables to raise the upper grilling surface
relative to the upper grilling surface.
10. The grill as recited in claim 4 wherein the plurality of motors
comprise three motors, and the cables are attached to the upper
grilling surface in a substantially triangular configuration.
11. The grill as recited in claim 1 further including a button that
is pressed by an operator to activate the leveling mechanism to
automatically level the upper grilling surface relative to the
lower grilling surface.
12. A grill comprising: a lower platen assembly including a lower
grilling surface; an upper platen assembly pivotally attached to
the lower platen assembly, wherein the upper platen assembly
includes an upper grilling surface; and a leveling mechanism to
automatically level the upper grilling surface relative to the
lower grilling surface, wherein the leveling mechanism includes: a
plurality of motors that each independently move a portion of the
upper grilling surface to level the upper grilling surface relative
to the lower grilling surface, wherein each of the plurality of
motors includes a rotatable shaft having an end, wherein a disc is
attached to the end of the shaft, a cable associate with each of
the plurality of motors having a first end and a second end,
wherein the first end of each of the cables is attached to one of
the discs and the second end of each of the cables is attached to
the upper grilling surface, wherein the upper grilling surface is
suspended from the cables, a control that independently controls
each of the plurality of motors, and a current sensor that senses
current in each of the plurality of motors.
13. The grill as recited in claim 12 wherein, when the leveling
mechanism is activated, the plurality of motors lower the upper
grilling surface onto the lower grilling surface, wherein each of
the plurality of motors sequentially raises the portion of the
upper grilling surface and the current in each of the plurality of
motors changes when the upper grilling surface lifts from the lower
grilling surface, wherein the current sensor detects a change in
the current, and wherein calibration settings of each of the
plurality of motors when the current sensor detects that the change
in the current is over a threshold value are stored in the control
to define a calibration point.
14. The grill as recited in claim 12 wherein food is grilled in a
gap between the lower grilling surface and the upper grilling
surface, the current in each of the plurality of motors changes
when the upper grilling surface lifts from the food, the current
sensor detects the change in the current, and a size of the gap is
determined to recognize the food and determine cooking
parameters.
15. The grill as recited in claim 14 wherein the cooking parameters
are one of a cooking time, a cooking temperature and a gap
distance.
16. A method of calibrating a grill comprising the steps of:
lowering an upper grilling surface of an upper platen assembly onto
a lower grilling surface of a lower grilling assembly; and
automatically leveling the upper grilling surface relative to the
lower grilling surface with a leveling mechanism, wherein the
leveling mechanism includes a plurality of motors that each move a
portion of the upper grilling surface.
17. The method as recited in claim 16 wherein the step of
automatically leveling the upper grilling surface includes:
lowering the upper grilling surface onto the lower grilling
surface, operating each of the plurality of motors independently
and sequentially to raise the portion of the upper grilling
surface, detecting a current in the each of the plurality of the
motors, determining when a change in the current is over a
threshold value, storing calibration settings of the each of the
plurality of motors when the change in the current is over the
threshold value, and employing the calibration settings of each of
the plurality of motors to determine a calibration point of the
upper grilling surface that levels the upper grilling surface
relative to the lower grilling surface.
18. The method as recited in claim 17 further including the step of
repeating the step of automatically leveling the upper grilling
surface for each of the plurality of motors.
19. The method as recited in claim 16 further including the steps
of: placing food on the lower grilling surface, lowering the upper
grilling surface onto the food, detecting a change in current when
the upper grilling surface lifts from the food, determining a size
of a gap between the upper grilling surface and the lower grilling
surface when the upper grilling surface contacts the food, and
determining cooking parameters based on the size of the gap.
20. The method as recited in claim 19 wherein the cooking
parameters are one of a cooking time, a cooking temperature and a
gap distance.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a national stage application of
International Application No. PCT/US2006/015157, filed on Apr. 20,
2006, the entire disclosure of which is hereby expressly
incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to a grill that
automatically calibrates a gap between an upper grilling surface
and a lower grilling surface.
[0003] Grills or griddles are used to cook various foods, such as
hamburgers. In one prior grill, the sides of the food are grilled
separately. The food is placed on a grilling surface, grilling the
side of the food that contacts the grilling surface. After that
side of the food is cooked, the food is manually flipped to cook
the opposite side. After the food is cooked, the food is manually
removed from the grill for serving.
[0004] In another prior grill, both sides of the food are grilled
simultaneously. After manually programming the type of food into a
control unit, the food is placed on a lower grilling surface. An
upper platen assembly having an upper grilling surface is then
lowered onto the food, positioning the food in a gap between the
upper and lower grilling surfaces to simultaneously grill both
sides of the food. After a predetermined amount of time has passed,
the upper platen assembly raises, and the food can be manually
removed from the grill.
[0005] To ensure optimal performance, the upper grilling surface
should be level to ensure that the upper grilling surface uniformly
contacts the food. If the upper platen assembly is not level, a
service technician must travel to the site to manually calibrate
the grill. This requires additional cost and labor.
[0006] Hence, there is a need in the art for a grill that
automatically calibrates a gap between an upper grilling surface
and a lower grilling surface and that overcomes the drawbacks of
the prior art.
SUMMARY OF THE INVENTION
[0007] A grill includes an upper platen assembly pivotally attached
to a lower platen assembly. The lower platen assembly and the upper
platen assembly each include a respective grilling surface. When
the upper platen assembly is lifted by an operator to a raised
position, the lower grilling surface is exposed. Food items are
placed on the lower grilling surface by the operator for cooking.
The upper platen assembly is pivoted downwardly to a lowered
position, positioning the food items in a gap between the lower
grilling surface and the upper grilling surface.
[0008] The upper platen assembly includes three motors encased in a
shell. A control operates and controls the three motors. The motors
each operate independently to rotate a shaft including a disc. The
upper grilling surface suspends from cables. A first end of each
cable is attached to the upper grilling surface, and an opposing
second end of each cable is attached to one of the discs.
[0009] The grill is automatically calibrated to ensure that the
upper grilling surface is level. An operator presses a button to
initiate the auto-calibration sequence. The upper grilling surface
is lowered to contact the lower grilling surface. One motor is then
operated to rotate the shaft, raising a portion of the upper
grilling surface. A current sensor detects the current in the
motor. When the upper grilling surface is slightly lifted from the
lower grilling surface, the current of the motor changes. When the
percent change in the current increases over a threshold value, the
position of the upper grilling surface and the motor setting are
stored in the control. The calibration steps are then repeated.
[0010] The calibration steps are then performed by the other two
motors individually and sequentially. After the calibrations steps
are performed by all three motors, the upper grilling surface is
level.
[0011] The grill also automatically recognizes a food item placed
on the lower grilling surface. An operator presses a button to
initiate a cooking cycle. The upper grilling surface lowers towards
the lower grilling surface and onto the food items. When the upper
grilling surface lifts from the food items on the lower grilling
surface, the current in the motors changes. When the current sensor
detects that the current changes, the size of the gap between the
upper grilling surface and the lower grilling surface is
determined, indicating the size of the food item. Based on the size
of the food item, the cooking parameters of the grill are
determined.
[0012] These and other features of the present invention will be
best understood from the following specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The various features and advantages of the invention will
become apparent to those skilled in the art from the following
detailed description of the currently preferred embodiment. The
drawings that accompany the detailed description can be briefly
described as follows:
[0014] FIG. 1 schematically illustrates a perspective view of a
grill of the present invention in a lowered position;
[0015] FIG. 2 schematically illustrates a perspective view of the
grill in a raised position;
[0016] FIG. 3 schematically illustrates a perspective view of the
grill in a closed position with a shell removed;
[0017] FIG. 4 schematically illustrates a top view of the grill
with the shell removed;
[0018] FIG. 5 schematically illustrates a perspective view of a
disc and a cable of a motor;
[0019] FIG. 6 schematically illustrates a side view of the motor
when rotating the disc in a first direction; and
[0020] FIG. 7 schematically illustrates a side view of the motor
when rotating the disc in a second opposite direction.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] FIGS. 1 and 2 illustrate illustrates a grill 20 in a lowered
position and a raised position, respectively. The grill 20 includes
a lower platen assembly 22 and an upper platen assembly 24
pivotally attached to the lower platen assembly 22 by a hinge 28. A
handle 26 on the upper platen assembly 24 can be grabbed by an
operator to pivot the upper platen assembly 24 relative to the
lower platen assembly 22 between the lowered position and the
raised position. The lower platen assembly 22 and the upper platen
assembly 24 each include a respective grilling surface 30 and 32.
When the upper platen assembly 24 is lifted by an operator to the
raised position, the lower grilling surface 30 is exposed.
[0022] Food items 34 are placed on the lower grilling surface 30 by
the operator for cooking. In one example, the food items 34 are
hamburgers. The operator grabs the handle 26 and pivots the upper
platen assembly 24 downwardly to the lowered position, positioning
the food item 34 in a gap 36 between the lower grilling surface 30
and the upper grilling surface 32. An arm 42 contacts the lower
grilling surface 30 to provide a mechanical stop that defines the
gap 36 between the upper grilling surface 32 and the lower grilling
surface 30. The grilling surfaces 30 and 32 are heated by a heater
(not shown) to cook the food items 34.
[0023] As shown in FIGS. 3 and 4, the upper platen assembly 24
includes a leveling mechanism 38 that automatically levels the
upper grilling surface 32 relative to the lower grilling surface
30. The leveling mechanism 38 includes three motors 46a, 46b and
46c encased in a shell 44 (shown in FIGS. 1 and 2). Each of the
motors 46a, 46b and 46c operate independently to level a portion of
the upper grilling surface 32. A control 78 independently controls
the three motors 46a, 46b and 46c. Although three motors 46a, 46b
and 46c are illustrated and described, it is to be understood that
any number of motors 46a, 46b and 46c can be used. The motors 46a,
46b and 46c each operate to rotate a shaft 48a, 48b and 48c,
respectively. Each shaft 48a, 48b and 48c rotates a respective disc
52a, 52b and 52c having a respective groove 54a, 54b and 54c.
[0024] The upper grilling surface 32 suspends from cables 58a, 58b
and 58c. A first end 60a, 60b and 60c of each cable 58a, 58b and
58c, respectively, is attached to an upper surface 88 of the upper
grilling surface 32 by an attachment member 62a, 62b and 62c,
respectively. As shown in FIG. 5, an opposing second end 64a, 64b
and 64c of each cable 58a, 58b and 58c is attached in the grooves
54a, 54b and 54c, respectively, of the disc 52a, 52b and 52c,
respectively, such that a portion of each of the cables 58a, 58b
and 58c is received in a groove 54a, 54b and 54c, respectively.
Although cables 58a, 58b and 58c are illustrated and described, it
is to be understood that metal drive belts can be employed.
[0025] Returning to FIG. 4, the cable 58a is attached near a first
corner 66 of the upper grilling surface 32 with the attachment
member 62a, and the cable 58b is attached near a second corner 68
of the upper grilling surface 32 with the attachment member 62b. An
edge 70 is located between the first corner 66 and the second
corner 68. The third cable 58c is attached to the upper grilling
surface 32 with the attachment member 62c at a location between a
third corner 72 and a fourth corner 74 of the upper grilling
surface 32. In one example, the attachment member 62c is
substantially centrally between the third corner 72 and the fourth
corner 74. An edge 76 opposite to the edge 70 is located between
the third corner 72 and the fourth corner 74. Therefore, the cables
58a, 58b and 58c are attached to the upper grilling surface 32 in a
substantially triangular pattern. However, it is understood that
any configuration of the cables 58a, 58b and 58c is possible. Each
of the motors 46a, 46c and 46c independently move and level a
portion of the upper grilling surface 32 that is near the
respective attachment members 62a, 62b and 62c.
[0026] As shown in FIG. 6, as the motor 46a rotates the disc 52a in
a first direction A, the cable 58a lengthens, lowering the upper
grilling surface 32 toward the lower grilling surface 30. As shown
in FIG. 7, as the motor 46a rotates the disc 52a in an opposing
second direction B, the cable 58a shortens and wraps around the
disc 52a, raising the upper grilling surface 32 away from the lower
grilling surface 30. Although only the motor 46a, the disc 52a and
the cable 58a are illustrated and described, the motors 46b and
46c, the discs 52b and 52c and the cables 58b and 58c operate in a
similar manner.
[0027] The grill 20 is automatically calibrated to ensure that the
gap 36 is maintained at the desired size between the lower grilling
surface 30 and the upper grilling surface 32. By calibrated, it is
meant that the upper grilling surface 32 is level relative to the
lower grilling surface 30 to ensure proper cooking of the food
items 34 in the grill 20. In one example, the grill 20 is
calibrated daily. If the upper grilling surface 32 becomes unlevel
during the day, the calibration steps performed the following day
will correct this. However, if the operator notices that the upper
grilling surface 32 has become unlevel during use of the grill 20,
for example by observing the quality or appearance of the food
items 34, the operator can press a button 84 to initiate the
auto-calibration sequence, as described below.
[0028] When the grill 20 is first used on a given day, an operator
presses the button 84 to initiate the auto-calibration sequence
that levels the upper grilling surface 32. The button 84
communicates with the control 78. The control 78 sends a signal for
the motors 46a, 46b and 46c to rotate the respective shafts 48a,
48b and 48c in the direction A, lengthening the respective cables
58a, 58b and 58c and lowering the upper grilling surface 32 onto
the lower grilling surface 30, providing a hard stop for the upper
grilling surface 32 and providing slack in the cables 58a, 58b and
58c.
[0029] A current sensor 80 detects the current in the windings of
each of the motors 46a, 46b and 48c. In one example, the current
sensor 80 is a Hall-Effect sensor. However, it is to be understood
that any type of sensor can be employed. When the upper grilling
surface 32 raises and lifts from the lower grilling surface 30, the
weight of the upper grilling surface 32 is transferred from the
lower grilling surface 30 to the cables 58a, 58b and 58c. When the
cables 58a, 58b and 58c begin to sustain the weight of the upper
grilling surface 32, the tension in the cables 58a, 58b and 58c
increases and therefore the current in the windings of the motor
46a, 46b and 46c changes.
[0030] After the upper grilling surface 32 is lowered onto the
lower grilling surface 30, one motor 46a is operated to rotate the
shaft 48a in the direction B, wrapping the cable 58a around the
disc 52a to shorten and remove any slack in the cable 58a and raise
the upper grilling surface 32. As the shaft 48a rotates and the
upper grilling surface 32 is lifted, the current of the windings of
the motor 46a is detected by the current sensor 80. As the upper
grilling surface 32 is lifted, the current is detected at each
location of the upper grilling surface 32. When the current sensor
80 detects a change in the current in the windings of the motor
46a, this indicates that the upper grilling surface 32 has lifted
from the lower grilling surface 30. When the percent change in the
current increases over a threshold level, the settings of the motor
46a and the location of the upper grilling surface 32 are stored in
the control 78.
[0031] The calibration steps are then repeated. The motor 46a
rotates the shaft 48a in the direction A to lower the upper
grilling surface 32 onto the lower grilling surface 30. The motor
46a is again operated to rotate the shaft 48a in the direction B,
wrapping the cable 58a around the disc 52a to shorten and remove
any slack in the cable 58a. The current of the windings of the
motor 46a is detected by the current sensor 80. When the percent
change in the current increases over a threshold level, the
settings of the motor 46a and the location of the upper grilling
surface 32 are stored in the control 78 and compared to the
settings of the motor 46a and the location of the upper grilling
surface 32 previously stored in the control 78. If the settings of
the motor 46a and the location of the upper grilling surface 32
match within a given range, these values are stored and indicate
the calibration settings of the motor 46a. If the settings of the
motor 46a and the location of the upper grilling surface 32 do not
match, the calibration steps are repeated until they do match
within a given range to settings determined in the previous set of
calibration steps. By repeating the calibrating steps more than
once, accurate calibration can be ensured.
[0032] Although it has been disclosed that the calibration settings
of the motor 46a are determined by detecting a percent change in
the current over a threshold level, it is to be understood that the
calibration settings of the motor 46a can be determined by
detecting a specific current or an average current.
[0033] The calibration steps performed by the motor 46a are then
repeated by the motors 46b and 46c individually and sequentially.
Although the motor 46a is described as performing the calibration
steps first, it is to be understood that the motors 46a, 46b and
46c can perform the calibration steps in any order. Before each
motor 46a, 46b and 46c performs the calibration steps, the upper
grilling surface 32 is lowered onto the lower grilling surface 30.
After all the motors 46a, 46b and 46c perform the calibration
steps, the calibration settings of each of the motors 46a, 46b and
46c that result in the leveling of the upper grilling surface 32
are stored in the control 78. A calibration point of the upper
grilling surface 32 is defined when each of the motors 46a, 46b
operate in the calibration settings, resulting in the upper
grilling surface 32 being level. Alternately, the motors 46a, 46b
and 46c are calibrated at the same time.
[0034] Additionally, the grill 20 automatically recognizes a food
item 34 that is to be cooked in the grill 20. After the food item
34 is placed on the lower grilling surface 30, the operator grabs
the handle 26 to lower the upper platen assembly 24 or presses a
button 86 to initiate a cooking cycle. The button 86 communicates
with the control 78. The control 78 actuates the motors 46a, 46b
and 46c to lower the upper grilling surface 32 towards the lower
grilling surface 30. The upper grilling surface 32 lowers to a
predetermined location and compresses the food items 34 between the
upper grilling surface 32 and the lower grilling surface 30 to sear
the food items 34.
[0035] The motors 46a, 46b and 46c are then operated to rotate the
respective shafts 48a, 48b and 48c in the direction B, wrapping the
respective cables 58a, 58b and 58c around the respective discs 52a,
52b and 52c to shorten and remove the slack in the cables 58a, 58b
and 58c and raise the upper grilling surface 32. As the shafts 48a,
48b and 48c rotate, the current of the windings of the motors 46a,
46b and 46c is detected by the current sensor 80.
[0036] When the current sensor 80 detects that the percent change
in the current of the windings of the motors 46a, 46b and 46c
increases over a threshold level, this indicates that the upper
grilling surface 32 has lifted from the food items 34. The control
78 determines the size of the gap 36 between the upper grilling
surface 32 and the lower grilling surface 30 based the settings of
the motor 46a, 46b and 46c and the calibration point. The size of
the gap 36 indicates the size of the food item 34. Based on the
size of the food item 34, the cooking parameters of the grill 20
are determined. The cooking parameters are programmed into the
control 78. For example, based on the size of the gap 36, the
cooking time, the cooking temperature and the size of the gap 36
during cooking of the food items 34 are determined. The control 78
sets the temperature of the heaters on the upper grilling surface
32 and the lower grilling surface 30, the size of the gap 36
between the upper grilling surface 32 and the lower grilling
surface 30, and the cooking time. After the cooking time has
passed, the upper platen assembly 24 raises, allowing an operator
to remove the food items 34 from the lower grilling surface 30.
[0037] Alternately, the size of the gap 36 is determined by
detecting when the upper grilling surface 32 contacts the food item
34 based on the detected current.
[0038] The foregoing description is only exemplary of the
principles of the invention. Many modifications and variations are
possible in light of the above teachings. It is, therefore, to be
understood that within the scope of the appended claims, the
invention may be practiced otherwise than using the example
embodiments which have been specifically described. For that reason
the following claims should be studied to determine the true scope
and content of this invention.
* * * * *